Yeah, I know.
I believe it would take a long time to finish new os, but my main purpose is learn base knowledge of a operating system, so I just implement simple one first step.
Could you give some suggestions, websites, books, experiences? Thanks.

It is possible to start writing a new OS. Linux was originally created by one person. This means you have a remote chance of gaining fame.
1) Decide on the functions and appearance of your OS. When you start the actual coding do not deviate from the original plan.
2) Use as many subroutines as possible. Proper use of subroutines will reduce the number of bugs. It will be easier to trace them. It will also make it easier to make any expansion.
Best of luck.